The police chief said Mossad had "insulted" Dubai and Western countries whose fraudulent passports were used by suspects in the assassination.

Investigation expanding

And a UAE newspaper reported that Dubai had also asked the US Federal Bureau of Investigation (FBI) to look into prepaid credit cardsissued by the Meta Financial Group's MetaBank which the suspects used.

Citing an FBI source, The National newspaper said the investigation would look into any Israeli involvement in the killing.

Quoting Dubai police, the newspaper said: "Thirteen of the 27 suspects used prepaid MasterCards issued by MetaBank, a regional American bank, to purchase plane tickets and book hotel rooms."

MetaBank said it followed proper procedures when it issued the cards.

Authorities told the bank that the suspects appeared to have used stolen passports to get employment with US companies, MetaBank said in a statement on Tuesday.

Dubai police have published details of 26 suspects together with passport photographs, and claim to have DNA evidence of the identity of at least one of the killers.

As a consequence of the assassination, UAE officials say they will prevent Israeli citizens travelling on foreign passports from entering the country.

Dubai police last Sunday issued a statement saying the "killers used the drug succinylcholine to sedate al-Mabhouh before they suffocated him" and that "assassins used this method so that it would seem that his death was natural".

Al-Mabhouh's killing has led investigators to Britain, Ireland, Australia and Germany - countries whose passports the assassins allegedly used.